LONDON -- Trial began Thursday for three men charged with helping the London Transport suicide bombers, with a prosecutor saying the defendants scouted locations.

Neil Flewitt, the prosecuting attorney, said the defendants traveled to London with Hasib Hussain, one of the bombers, in December 2004, The Daily Telegraph reported. They visited a number of locations that resembled the eventual targets, along with other popular tourist destinations, Flewitt told the court.

"It is the prosecution case that the defendants were associated with and shared the belief and objectives of the London bombers and so were willing to assist them in one particular and important aspect of their preparation for the London bombings," he said.

Scores of people were killed July 7, 2005, when the four bombers hit three underground trains and a bus. Jurors saw videotape from security cameras that showed the bombers traveling to London, splitting up and boarding the trains where they detonated their backpack bombs.